I like land battles concept, but when I was reading Honor Harrington series, it was clearly said: who controls the space/orbit controls the planet. Winning space/orbital battle means surrender/destroying the planet.
Space invasions like in Star Wars would be possible only with planetary shields preventing bombardment. If bombardment is available no commanders would send troops down. Just some rockets/lasers/whatever before sending a message "surrender or die".
This does actually get addressed somewhere in the series. Once you control the orbitals you have the capability to destroy the planet with the weapons they were talking about. This led to a convention that you surrendered when someone gained control there. If you did not then the whole "Solarian League", "Eridani Edict" was nullified. A planet that did not surrender and was then bombarded did not trigger the immediate attack of the Solarian League on the attacking force. In other words this was a convention of war and not an absolute truism that precluded any other result. In effect we have the same capabilities in Aurora to destroy the planet for useable colonization, or risk your ground forces fighting on the ground to capture the territory and resources/improvements already present.
Brian
